Blueprint

Introduction

Blueprints are data objects. The essential idea is that you write subclasses of blueprint.Blueprint with fields that define the general parameters of their values (e.g. an integer between 0 and 10). When you instantiate a blueprint, you get a "mastered" blueprint with well-defined values for each field. Mastered blueprints may define special "generator" instance methods that build final objects from the master.

Think of it as prototypal inheritance for Python! (Yeah, I probably don't know what I'm talking about.)

Most of the big moving parts have their documentation, often with examples, in the docstring. Blueprint is best played with at the command line, trying out how things work. For the impatient, an example:

Now, we can take our reified master data object and do something with it--use it as-is, or build another entity using the generated data.

Fields and Generators

Blueprints are data objects. By default, every member of a blueprint is treated as a field, either static or dynamic. Static fields are simple data attributes. Dynamic fields are callable objects that take one positional argument, the blueprint on which they are being called.

Dynamic fields make blueprints quite useful. A few basic fields are provided to get you started, and Blueprints themselves can be used as fields. Fields are designed to be nestable. They can rely upon each other too--use the blueprint.depends_on decorator to declare these dependencies.

If you really must have a callable method on your mastered blueprint, use the blueprint.generator decorator (or mark your callable object with the is_generator flag). These are called "generators" ("contractors" in squidi's terminology) because they're intended to be used to generate your final entity, whether it be a dict or a WAD file.

Tags

Blueprints automatically organize themselves using tags (domains in squidi's parlance). A direct descendant of Blueprint has its own tag repository (blueprint.taggables.TagRepository), which all its subclasses will share. So, in the above example, you can queryWeapon.tag_repo.query(with_tags=('piercing')) and receive set([Spear, PointedStick]).

Blueprints are also automatically tagged by their class name (and their ancestor superclass names!), with camel-cased words separated out. So CaveMan will automatically get the tags set(['cave', 'man', 'actor']).

Factories

Factories put all the pieces together--they're rather a blueprint factory. Say that you want an item drop that selects from a few common Weapon blueprints and adds a couple magical Mods to make it cooler. Here's our second mod: